Advanced Materials Research Vols. 148-149

Abstract: According to the requirements of integral Stereolithography (integral SL) System, a new direct slicing method with SolidWorks for integral Stereolithography System is developed. Slicing function of SolidWorks is employed to slice CAD models directly, and section image of 3D models can be obtained and saved as image format. Dynamic graphic masks for the integral SL System are created according to the cross-section images that obtained through the slicing method, and then 3D real prototyping can be fabricated conveniently. A 3D cup model is sliced with this method, and the cup prototyping also is built with integral SL System. This experiment shows that direct slicing CAD models with Solidworks can be used for integral SL system, and the method of direct slicing CAD models can improve the efficiency of slicing process. Compared with the STL format files slicing method, the new method does not need to inspect and repair models data, and it can achieve high accuracy of layer section profile. The direct slicing method provides a basis for integral SL system to fabricate objects with high accuracy.

Abstract: PbWO4 crystals were synthesized by homogeneous precipitation in formamide (FA)/H2O solution, where the content of FA was found to play crucial role in the morphology of the final products. PbWO4 crystals with various morphologies, such as pagoda, tetra-bipyramid, and bundle of rods, were obtained with an increase of the content of FA. The products were characterized by XRD and photoluminescence measurements.

Abstract: The dispersed particles of magnetic fluid form stable chain-like clusters under the magnetic field, and shows “the flowing is controllable and the shape is controllable” effect. Based on this characteristic, using migration magnetic acted on the magnetic fluid, the object directional migration can be realize, then the magnetic fluid form ribbon at the same time, has the similar fluctuation behavior. The magnetic fluid aerosol migration principle, the aerosol magnetic circuit design, the magnetic field strength and the magnetic force were separately discussed in this paper. The magnetic fluid hover height using the MSL micrometer dial has determined and aerosol migration feasibility has confirmed using the experiment.

Abstract: ZnO nanorods doped with Ce4+ ions have been synthesized by a solvothermal method. The concentration level of Ce4+ additive was varied systematically from 1 to 10 mol. %. The structural and optical properties of Ce4+ -doped nanostructures are investigated using X-ray diffraction, transmission electron micrograph, UV-visible absorption and photoluminescence Spectroscopy. The results showed that the concentration increase of Ce4+ doping induce the enhancement of photoluminescence.

Abstract: This single-molecule C60 system with two atomic lines as left input electrode and right output electrode is calculated by simulation using the Green，s function method based on the density function theory. The characteristics of current transmission of single-molecule C60 which include I-V curve, current-temperature changing and transmission spectrum are given. The resonant switching is shown from the single-molecule C60 transmission spectrum, differential negative resistance (NDR) and the high ratio of current peak and current valley are also indicated from the I-V curve. The conclusions can be explained using band theory very well and finally the impact of temperature for current of this C60 single-molecule system is discussed etc.

Abstract: We report the structural and optical properties of a-Al2O3 film grown on porous silicon substrate using sol-gel method. The results indicated that a-Al2O3 film were grown after it sintering at 1200 °C for 1 hour and the scanning electron microscopy image shows the a-Al2O3 film has a nanostructure. From the photoluminescence spectrum, it shows that a narrow purple emission peak. This proved porous silicon is a good substrate to grow a-Al2O3 film.

Abstract: Zinc sulfide nanoparticles as undoped and doped with nickel have been prepared by the reaction of Zn(CH3COO)2 and Ni(CH3COO)2 with potassium O-ethyldithiocarbonate (ethyl xanthate, C2H5OCS2k) at 80 in N, N - dimethylformamide (DMF) solution for 24 h. The structures of the products were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM), and their optical properties were studied by UV-Vis spectroscopy. The photocatalytic experiment by degrading methyl orange in aqueous solution under UV light indicated that the degradation efficiency of Ni (6%)-doped ZnS nanoparticles increased to 75% with comparison to 43% of degradation efficiency for undoped ZnS nanoparticles.

Abstract: ZnO microsturctures with flower-like and sphere-like morphologies have been successfully synthesized in ethylene glycol (EG) -water solution at 160 through a hydrothermal method. The volume ratio of EG to H2O plays an important role on the morphology control of ZnO. CH3COONH4 and NaOH were used as hydroxide source as well as complexing agents. The ZnO samples were characterized by XRD, FTIR and SEM. The optical properties of the final products were investigated by UV-vis absorption spectrometer and photoluminescence. The formation mechanism was also discussed.

Abstract: Recent years have therefore seen growing interest in gear precision forging to net-shape form of forge bevel, spur and helical gears, as an alternative to conventional manufacturing. In this paper, gear precision forging processes are simulated by using metal forming finite element code DEFORM-3D. The investigations of gear precision forging processes are conducted with perform forging and final forging processes. The processes of completely closed-die forging, moving-die forging and central divided flow forging processes are investigated for spur gears. The effect of different processes on the distribution of effective stress in the workpieces and forging loads are given. The purpose of this study is to introduce a new method, a so-called floating-relief method which applied to the forging of spur gears. It indicated that the flowing properties of the gear billet have a higher improve than that of conventional forging process. And the forging load obtained by using this new precision forging technology is decline sharply. The floating-relief method for gear precision forging is a sound process in the practical application.

Abstract: Making use of the finite element analysis software ANSYS, we calculated the effects of different processing parameters on temperature, cooling rate and superheating time of Fe3Al melt in aluminothermic reaction to prepare bulk Nanocrystalline Fe3Al. The results showed that, with the increase of substrate thickness and reduction of reactant’s quantity, cooling rate of the Fe3Al melt at the initial cooling stage became larger, while the melt purification became worse. With the increase of argon pressure, the Fe3Al melt cooled a little quicker. The cooling rate of melt cooled by glass substrate was lower than that of the melt cooled by 1045 steel and Cu substrate, while the melt purification became better. With the increase of Al2O3, Fe3Al diluents content, the cooling rate at the initial cooling stage became lower, and the melt purification became worse. The experiment verified that the calculated results were in good coincident with the experimental results.